Chemical mechanical polishing device including a polishing pad and cleaning method thereof and method for planarization

ABSTRACT

A chemical mechanical polishing device used to polish a wafer according to the present invention includes a polishing table, a polishing pad, a slurry supply device, a wafer carrier and a high-pressure liquid cleaning device. The polishing pad is disposed on the polishing table to polish the wafer. The slurry supply device is disposed on the polishing table to supply the slurry. In addition, the wafer carrier is disposed the polishing table to carry the wafer in such a manner that the wafer is brought into contact with the polishing pad. Besides, the high-pressure cleaning device is disposed on the polishing table to remove the impurities on the polishing pad by high-pressure liquid.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a semiconductor process and a semiconductor processing device as well as a cleaning method thereof, and more particularly to, a chemical mechanical polishing device including a polishing pad and a cleaning method thereof.

2. Description of Related Art

Planarization is a high technology for dealing with high density microlithography in semiconductor manufacturing technologies because a precise pattern transfer can be achieved only on a planar surface with any wavy profile so as to prevent light scattering during an exposure period. Currently, a chemical mechanical polishing method is the only one that can provide very-large scale integration (VLSI), even ultra-large scale integration (ULSI) with a global planarization. Hence, a current planarization process of a wafer is accomplished by the chemical mechanical polishing method.

A principle of the chemical mechanical polishing method exploits a mechanical principle of similar to “grinding blade”, working with a suitable chemical reagent to grind a wavy profile of the wafer's surface disposed on the polishing pad.

Roughness of the polishing pad deteriorates after completing a polishing process. In common, the conventional chemical mechanical polishing device maintains its roughness by using an adjuster. However, this always causes a problem of peeling of diamond granules disposed on the adjuster on the polishing pad, which results a crack of the wafer. In addition, a residual paste after polishing is solidified, which in turn accordingly scratches the wafer. Besides, diamond granule disposed on the adjuster also causes damages to the polishing pad. Accordingly, a grind efficiency of the chemical mechanical polishing device is affected.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to provide a chemical mechanical polishing device including a polishing pad and a cleaning method thereof to avoid a polishing pad's damage caused by diamond granules disposed on the adjuster, which always happens in the conventional technology.

The present invention is further directed to provide a planarization method, which evens a wavy layer by using the chemical mechanical polishing device during a processing period.

A chemical mechanical polishing device used to polish a wafer according to the present invention includes a polishing table, polishing pad, a slurry supply device, a wafer carrier and a high-pressure liquid cleaning device. The polishing pad is disposed on the polishing table to polish the wafer. The slurry supply device is disposed on the polishing table to supply the slurry. In addition, the wafer carrier is disposed the polishing table to carry the wafer in such a manner that the wafer is brought into contact with the polishing pad. Besides, the high-pressure cleaning device is disposed on the polishing table and removes the impurities on the polishing pad by high-pressure liquid.

According to a chemical mechanical device of one embodiment of the present invention, the high-pressure liquid cleaning device includes a high-pressure liquid transport exit, a pipe and a pressured pump, wherein the high-pressure liquid transport exit is a nozzle, a spray nozzle or a water blade nozzle, all of which are used to spray water onto the polishing pad. In addition, the pressured pump is used to pump water into the pipe and adjust a magnitude of the water pressure. In addition, a further disposition arrangement is a transmission device that is a rotation rod for changing a water-ejected direction of the high-pressure nozzle. Also, a mask is further disposed to limit a range of the water-ejected direction of the high-pressure nozzle. Besides, a pumping-gas device is further disposed to exhaust water vapor. In addition, the slurry supply device comprises a slurry supply pipe and a water-supplied pipe.

The present invention is further directed to provide a cleaning method for a chemical mechanical polishing pad. First of all, the polishing pad with impurities is provided and then the impurities on the polishing pad are removed by using the high-pressure cleaning device.

The present invention further provides a planarization method. First of all, a layer to be evened is provided. Then, the layer to be evened is planarized by using the chemical mechanical polishing device to form a planarized structure. In addition, the chemical mechanical polishing device comprises a polishing table, a polishing pad, a slurry supply device, a wafer carrier and a high-pressure liquid cleaning device. Besides, the polishing pad is disposed on the polishing table to grind the wafer; The slurry supply device is disposed on the polishing table to supply the slurry; the wafer carrier is disposed on the polishing table to support the wafer in such a manner that the wafer is brought into contact with the polishing pad; the high-pressure liquid cleaning device is disposed on the polishing table to transport the high-pressure liquid onto the polishing pad to remove the impurities on the polishing pad. Furthermore, the high-pressure cleaning device comprises a high-pressure liquid transport exit, a pipe and a pressured pump. Wherein the high-pressure liquid transport exit is used for spray water onto the polishing pad; the pipe is used for transporting water to the high-pressure liquid transport exit and the pressured pump is used for pumping water into the pipe and adjust a magnitude of the water pressure.

According the planarization method of the embodiment of the present invention, the high-pressure liquid transport exit is a nozzle, a spray nozzle or a water blade nozzle. In addition, a further disposition arrangement is a transmission device that is a rotation rod for changing a water-ejected direction of the high-pressure nozzle. Also, a mask is further disposed to limit a range of the water-ejected direction of the high-pressure nozzle. Besides, a pumping-gas device is further disposed to exhaust water vapor. In addition, the slurry supply device comprises a slurry supply pipe and a water-supplied pipe.

Since the present invention exploits a high-pressure water column instead of the conventional adjuster with diamond granules, the peeling of the diamond granules, which causes a crack of the wafer, can be prevented when the adjuster is forced to against the polishing pad. In addition, a utilization of rinsing a residual grinding paste by using the high-pressure water column can eliminate a wafer-scratched problem caused by the crystallized grinding paste's existing on the polishing pad. In addition, the high-pressure water column used by the present invention further alleviates damages of the polishing pad caused by the conventional adjuster's diamond granules and prolongs the life-span of the polishing pad. Moreover, the present invention further exploits a new chemical mechanical polishing device to replace the conventional chemical mechanical polishing device for proceeding with the planarization process.

The objectives, other features and advantages of the invention will become more apparent and easily understood from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a cross sectional view of a chemical mechanical polishing device of one embodiment of the present invention.

FIG. 2A-2C are cross sectional views of the flow process of one embodiment of the present invention.

FIG. 3A-3B are cross sectional views of the flow process of another embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.

FIG. 1 shows a cross sectional view of a chemical mechanical polishing device of one embodiment of the present invention. Referring to FIG. 1, a chemical mechanical polishing device 300 comprises a polishing table 301, a wafer carrier 302, a polishing pad 304, a slurry supplying device 305 and a high-pressure liquid cleaning device 310. In addition, the wafer carrier 302 is disposed on the polishing table 301 in such a manner that a wafer 312 is brought into contact with the polishing pad 304, and grasps the wafer 312 to be polished. The polishing pad 304 is disposed on the polishing table 301 to grind the wafer 312.

When proceeding with a grinding process, a liquid tank 308 in the slurry supply device 305 draws an amount of grinding paste 314 into a slurry supply pipe 306, which in turn transports the amount of grinding paste 314 onto the polishing pad 304. In addition, the slurry supply device 305 further comprises a water-supplied pipe (not shown) for transporting the deionized (DI) water onto the polishing pad 304.

After completing the chemical mechanical polishing process, the residual grinding paste is crystallized and remains on the polishing pad 304, which damages the wafer. The ejected water from the high-pressure liquid cleaning device 310 disposed on the polishing pad 304 can clean the polishing pad 304.

In one embodiment, a pressured pump 318 in the high-pressure liquid cleaning device 310 can draw a liquid, for example, water, into a pipe 316 and adjust a magnitude of the water pressure. Water is transported to a high-pressure liquid transport exit 315 through the pipe 316 so as to spray the water onto the polishing pad 304. The high-pressure liquid transport exit 315 can be changed to be a water-column nozzle, a water-spray nozzle or a water blade nozzle, depending on needs in a variety of cases. Moreover, the high-pressure liquid transport exit 315 is adjusted to a proper angle so as to spray water onto the polishing pad 304 to clean the impurities on the polishing pad 304 by using the high-pressure water column, the water spray or the water blade.

In this embodiment, a transmission device 320 is further disposed in the high-pressure liquid cleaning device 310 to change a water-ejected direction of the high-pressure liquid transport exit 315.

Furthermore, a pumping device 322 is disposed beside the chemical mechanical polishing device 300 and a mask 324 is disposed beside the high-pressure liquid cleaning device 310. Besides, the pumping device 322 is used for exhausting water vapor and the mask 324 is used for limiting a water-ejected range of the high-pressure nozzle.

It is noticeable that in the present invention, a disposition order of said each element and relative dispositions among these elements are not limited. That is, depending on needs of processing machines, users can proceed with any disposition arrangement.

In the following embodiment, an application of chemical mechanical polishing device of the present invention will be described in detail. FIG. 2A-2C shows cross sectional views of the flow process of the present invention. In one embodiment, taking an example of a manufacturing method for a shallow-trenched isolation structure, first of all, a substrate 400 is provided, as shown in FIG. 2A. An opening 406 is defined by a patterned hard mask layer 404 disposed on the substrate 400 and then a layer 408 to be planarized is disposed on the patterned hard mask layer 404 and the opening 406, wherein the layer 408 comprises material, for example, silicon-dioxide.

Subsequently, referring to FIG. 2B, the processes proceed with a planarization step by using the chemical mechanical polishing device to remove the layer 408 to be planarized disposed on the patterned hard mask layer 404. The chemical mechanical polishing device may be, for example, the chemical mechanical polishing device with the high-pressure liquid cleaning device, described above. Afterwards, the patterned hard mask layer 404 is removed to form the well-known shallow-trenched isolation structure, as shown in FIG. 2C.

Furthermore, the following description takes an example of a metal-embedded structure. FIG. 3A and FIG. 3B show cross sectional views of the flow processes of another embodiment of the present invention. Referring to FIG. 3A, first of all, a layer 500 is provided. The layer 500 has an opening 504 and a layer 506 to be planarized is disposed on the layer 500 and the opening 504. Subsequently, the processes proceed with a planarization step by using the chemical mechanical polishing device to remove the layer 506 to be planarized disposed on the layer 500. As a result, the resultant structure is shown in FIG. 3B. Likewise, the metal-embedded structure is formed by using the chemical mechanical polishing device described above in this embodiment.

In summary, Since the chemical mechanical polishing device of the present invention exploits the high-pressure water column cleaning device with an adjustable water-ejected angle to replace the conventional adjuster with diamond granules, while maintaining a roughness of the polishing pad, a wafer-cracked situation caused by the peeling of the diamond granules can be prevented when the adjuster is forced against the polishing pad. Furthermore, the high-pressure water column can only provide a certain portion of the wafer with the cleaning process so as to prevent crystallized grinding paste's scratching the wafer. In addition, the high-pressure water column has a minimal damage to the polishing pad to avoid reducing a grinding efficiency of the polishing pad and prolong a life-span of the polishing pad, thereby promoting a production yield. Moreover, the present invention further exploits the new chemical mechanical polishing device, instead of the conventional chemical mechanical polishing device, to proceed with the planarization process.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

1. A chemical mechanical polishing device, suitable for grinding a wafer, the chemical mechanical polishing device comprising a polishing table; a polishing pad, disposed on the polishing table and used for grinding the wafer; a slurry supply device, disposed on the polishing table; a wafer carrier, disposed on the polishing table and used for supporting the wafer in such a manner that the wafer is brought into contact with the polishing pad; and a high-pressure liquid cleaning device, disposed on the polishing table and used for transporting a high-pressure liquid onto the polishing pad to remove impurities on the polishing pad.
 2. The chemical mechanical polishing device according to claim 1, wherein the high-pressure liquid cleaning device comprises: a high-pressure liquid transport exit for spraying the liquid onto the polishing pad; a pipe for transporting the liquid to the high-pressure liquid transport exit; and a pressured tank for drawing the liquid into the pipe and adjusting a magnitude of the liquid pressure.
 3. The chemical mechanical polishing device according to claim 2, wherein the high-pressure liquid transport exit is a high-pressure nozzle, comprising a water column nozzle, a water-spraying nozzle, or a water blade nozzle.
 4. The chemical mechanical polishing device according to claim 3, further comprises a transmission device for changing a liquid-ejected direction of the high-pressure nozzle.
 5. The chemical mechanical polishing device according to claim 4, wherein the transmission device comprises a rotation rod.
 6. The chemical mechanical polishing device according to claim 2, further comprises a mask for limiting a liquid-ejected range of the high-pressure nozzle.
 7. The chemical mechanical polishing device according to claim 1, wherein the slurry supply device further comprises a slurry supply pipe and a water-supplied pipe.
 8. The chemical mechanical polishing device according to claim 1, further comprises a pumping device for exhausting liquid vapour.
 9. A method for cleaning a chemical mechanical polishing pad, comprising: providing a polishing pad on which impurities are disposed; and removing the impurities disposed on the polishing pad by using a high-pressure liquid.
 10. The method for cleaning a chemical mechanical polishing pad according to claim 9, wherein the high-pressure liquid comprises high-pressure water column, high-pressure water-spraying or high-pressure water blade.
 11. A planarization method, comprising: providing a layer to be planarized; and planarizing the layer to be planarized by using a chemical mechanical polishing device to form a planarized structure, wherein the chemical mechanical polishing device comprises: a polishing table; a polishing pad, disposed on the polishing table and used for grinding the wafer; a slurry supply device, disposed on the polishing table; a wafer carrier, disposed on the polishing table and used for supporting the wafer in such a manner that the wafer is brought into contact with the polishing pad; and a high-pressure liquid cleaning device, disposed on the polishing table and used for transporting a high-pressure liquid onto the polishing pad to remove impurities on the polishing pad.
 12. The planarization method according to claim 11, wherein the high-pressure liquid cleaning device comprising: a high-pressure liquid transport exit for spraying the liquid onto the polishing pad; a pipe for transporting the liquid to the high-pressure liquid transport exit; and a pressured tank for drawing the liquid into the pipe and adjusting a magnitude of the liquid pressure.
 13. The planarization method according to claim 12, wherein the high-pressure liquid transport exit comprises a water column nozzle, a water-spraying nozzle, or a water blade nozzle.
 14. The planarization method according to claim 11, wherein the layer to be planarized is a dielectric layer or a metal layer.
 15. The planarization method according to claim 11, wherein the slurry supply device further comprises a slurry supply pipe and a water-supplied pipe. 